Field of the Invention
The present invention relates to a work implement, an arm, and a work vehicle.
Background Information
With a large hydraulic excavator, because of the large size of the bucket, a great deal of power is needed for rotation, and two hydraulic cylinders are sometimes used. In a case such as this, the distal end of the arm branches in two, the distal ends of which are rotatably attached to the bracket of the bucket (see Japanese Laid-Open Patent Application 2006-132224, for example).
FIG. 11 shows the configuration of a boom 1800, an arm 1100, and a bucket 1200 in a conventional hydraulic excavator. In FIG. 11, the bucket 1200 is attached to the arm 1100 so that its opening faces to the rear of the vehicle.
With a hydraulic excavator such as this, a flat protector 1300 is disposed as a protective member to the distal ends of the arm 1100 so that soil excavated by the bucket 1200 will not fall into the space 1000S between the two distal ends of the arm 1100.
Meanwhile, if the arm 1100 should be twisted during the drive of the hydraulic excavator, there will be greater twisting at the forked portion of the distal end of the arm 1100. Accordingly, the protector 1300 is fixed to the arm 1100 at the portion on the proximal end part side, but is not fixed to the arm 1100 at the portion on the distal end part side, and a restricting member is attached to the arm 1100 so as to restrict movement resulting from this distortion. The conventional structure for attaching the protector 1300 to the arm 1100 will now be described.
FIG. 12 is a detail view of the distal end of the arm 1100, and shows a state in which the protector 1300 has been removed. As shown in the drawing, the distal end of the arm 1100 is divided into a first end component 1110 and a second end component 1120, and the above-mentioned spaces 1000S is formed between the first end component 1110 and the second end component 1120. A seat 1400 is provided to the surface of the aim 1100 so as to surround the space 1000S. The protector 1300 is bolted to this seat 1400.
As shown in FIG. 12, the seat 1400 is made up of a first seat 1410 disposed along the first end component 1110, a second seat 1420 disposed along the second end component 1120, and a third seat 1430 disposed on the edge on the boom 1800 (see FIG. 12) side of the space 1000S. Two bolts 1500 are disposed in the third seat 1430 in the width direction of the arm 1100, and four bolts 1500 are disposed in each of the first seat 1410 and the second seat 1420 along the lengthwise direction of the arm 1100.
FIG. 13 is a cross section of a state in which the protector 1300 is fixed to the seat 1400. FIG. 13 shows the contact portions of the first seat 1410 and the protector 1300, but the configuration is the same for the contact portions of the second seat 1420 and the protector 1300.
As shown in FIG. 13, the two bolts 1500 on the proximal end part side press the protector 1300 against the first seat 1410 via washers 1600. Thus, the protector 1300 is fixed to the first seat 1410 by the bolts 1500.
Meanwhile, substantially cylindrical collars 1700 having a large-diameter part 1710 and a small-diameter part 1720 are fitted to the two bolts 1500 on the distal end part side. FIG. 14 is a detail view of the area near a portion of the two bolts 1500 on the distal end part side in FIG. 13. These collars 1700 are pressed against the first seat 1410 by the bolts 1500 and thereby fixed to the first seat 1410.
In a state in which the hydraulic excavator is not operating, a gap is formed between the collars 1700 and the protector 1300, and the collars 1700 and the protector 1300 are not to touching. More precisely, in the axial direction of the collars 1700, a gap G1001 is formed between the large-diameter part 1710 and the protector 1300, and in the radial direction thereof, a gap G1002 is formed between the small-diameter part 1720 and the protector 1300.
Thus, the configuration is such that just the proximal end part side of the protector 1300 is fixed to the arm 1100, but the distal end part side of the protector 1300 is not fixed to the arm 1100 and restricts distortion of the protector 1300.